Agree, it's from the British Isles or UK thereabouts. I however don't agree that it's a fast plant. A fast plant would be something like cabomba that grows an inch a day.
Agreed hatonnia is a native plant, to me in the uk anyway. however I would suggest that it is a cold water plant. British rivers even in summer never get above 22C so cooler temperatures will suit this pretty plant much better.